Public actor (e.g. municipality)

The Olaya Herrera neighbourhood in Cartagena has been the focus of a series of projects that involve ecological restoration, environmental education, and community resilience building. These initiatives have centred around the restoration of the Ciénaga de la Virgen, an ecologically significant but heavily degraded coastal wetland bordering the neighbourhood. The primary goals of the projects in Olaya Herrera include the restoration of degraded mangrove ecosystems, mitigation of flooding and water pollution, strengthening community participation in environmental management, and promoting sustainable urban environments (ref 1, 2). The project is led by the EPA Cartagena, which coordinates actions such as collecting solid waste, planting timber trees and ornamental plants, and restoring green spaces that had become informal dumping grounds (ref 1). It also includes a community-led initiative called Los Guardabosques de Olaya that focuses on reforestation and environmental stewardship, it involves children, youth, and local mothers in reforesting mangrove areas around the Ciénaga de la Virgen. The community has established a mangrove nursery and employs innovative waste management practices, such as installing traps in canals to prevent solid waste from entering the Ciénaga (ref 2). The project also involves the private sector in 2022, the EPA led a campaign with local companies like Konfirma, Acuacar, and Pacaribe that focused on improving environmental health through the removal of 10 cubic meters of waste, promoting healthy living environments and fostering community participation in environmental monitoring and waste management practices​ (ref 4). Also, in collaboration with community leaders and local companies, the ANDI-TRASO Alliance supports large-scale reforestation and restoration activities in the southern parts of the Ciénaga de la Virgen adjacent to Olaya Herrera. The alliance plans to plant 40,000 mangrove seedlings (ref 6).

The Grand Parc des Aygalades project involves the creation of a 14-hectare metropolitan park (connecting Aygalades Park with Bougainville Park and François Billoux Park) that will connect the northern neighbourhoods of Marseille to the port located further south (Ref 1). This project is part of the green conversion of Marseille's northern districts, historically among the most disadvantaged areas in France (Ref 1). The Grand Parc des Aygalades project will enhance the city's greenery, reduce flood risks, create cool zones, restore and develop biodiversity, and significantly improve residents' quality of life and air quality (Ref 1, Ref 2). The environmental and social challenges include reconnecting the populations of these neighborhoods to green spaces, services, education, sports opportunities (Ref 2).
The park project includes redesigning urban infrastructure to improve rainwater absorption and reduce flood risks, addressing the issue of impermeable and artificialized soils that exacerbate flooding during heavy rainfall (Ref 1). It also involves renaturing a 17-kilometre-long stream currently buried under railway tracks, improving flood management and rainwater drainage (Ref 1, Ref 4). The project will also convert a heavily degraded former industrial site, requiring the rehabilitation of polluted soils (Ref 1). Additionally, creating green corridors aims to mitigate the heat island effect, particularly severe in these northern districts due to the high concentration of buildings and concrete surfaces, and the lack of green spaces. Public participation will be encouraged through information meetings, thematic workshops, and an online platform for submitting ideas and feedback (Ref 4).

The ReDuna project, initiated in 2014, focuses on restoring the sand dune ecosystem in Costa da Caparica (Almada) in response to severe coastal erosion exacerbated by sea-level rise and winter storms. It aims to strengthen the resilience of dunes to environmental pressures while restoring ecological balance. Actions include sand nourishment, the installation of willow sand fences, and the planting of 100,000 native species. Community engagement was a key factor, involving local residents, NGOs, and schools in maintenance and replanting efforts. The project has been successful, with significant biodiversity recovery, establishing deep-rooted vegetation, and stabilising the dunes. Ongoing monitoring and adaptive management are central to its strategy, ensuring long-term sustainability. The ReDuna project serves as a replicable model for similar coastal protection initiatives globally (Ref 1).

As part of France's New National Urban Renewal Program (NPNRU) and its strategy to enhance urban quality of life, the Urban Integrated Farm in Desclieux was established in 2021, with a particular emphasis on urban agriculture.
This project is implemented by the Centre de Culture Populaire Ypiranga de Pastinha Martinique (CCPYPM or Ypiranga Martinique) in collaboration with the city of Fort-de-France and is located in the socioeconomically disadvantaged Ravine-Bouillé neighborhood. It aims to create a farm on a 2-hectare former military site that previously housed fuel cisterns connected to the French Navy at Fort Saint-Louis. Since falling into disuse in the 1990s, only the reinforced concrete structures remain.
The farm will feature various activities, including a composting zone, a café, a beehive, a botanical trail, a play garden, and areas for crop and animal production. Additionally, it will house a decontamination and materials library and a public living space for community use. Overall, this site aims to serve educational, recreational, and socioeconomic purposes, enriching the local urban ecosystem.
Even though the intervention commenced in 2021 it has encountered several challenges since 2022 due to administrative hurdles. The implementers are currently awaiting temporary authorization to proceed. The primary obstacle remains the development and execution of a comprehensive soil decontamination plan. (Ref 2; 3; 4)

The regreening project is located in Seestadt Aspern, a newly developed urban area in Vienna's Donaustadt district. Two years after the completion of buildings, streets, and squares, the ground was reopened in 2022 to address the challenges posed by urban heat islands. Pavement was removed, and trees and shrubs were planted to provide shade, create insect habitats, and open seepage areas for rainwater. Additional features like benches, a water station, and water jets were installed to enhance the area's livability. These measures improve the overall quality of life, offering residents green spaces to relax and opportunities to cool down through water play.
The project spans three connecting squares in Seestadt: Wangari Maathai Square, Simone de Beauvoir Square, and Eva Maria Mazzucco Square. In 2022, Wangari-Maathai-Platz and Simone-de-Beauvoir-Platz underwent intensive regreening. By 2023, Eva-Maria-Mazzucco-Platz in the Seeparkquartier was similarly transformed with additional greenery and cooling features. Under the slogan "Out of the Asphalt," one of Europe's largest and most innovative urban development projects took a significant step toward improving quality of life.
In 2023, over 1,100 square meters of asphalt were removed and greened. This effort included the creation of 12 new green beds planted with grasses, perennials, and shrubs. The design also introduced two square-like recreation areas with existing seating elements surrounded by green beds, providing shaded, pleasant spaces for relaxation.
The Eva-Maria-Mazzucco square was designed by a local NGO specializing in citizen engagement in urban development, while the project's overall initiation and implementation were led by the City of Vienna, the Donaustadt district, and Wien 3420 Aspern Development AG. This collaborative effort demonstrates how regreening initiatives can mitigate heat islands, foster urban biodiversity, and create more attractive, livable spaces. (Ref. 1-3)

In 2024, Ozanam (a housing private company) and the French Development Agency (AFD) formalized a partnership to modernize an ecological wastewater treatment plant in Saint-Joseph, a neighborhood in Fort de France. The project focuses on replacing an outdated 30-year-old installation that no longer meets current standards with a plant-based water filtration system based on the ‘Rhizosph’air’ patent. This innovative treatment process utilizes "filter gardens," which combine mechanical systems, a gravity network, and a phytoremediation approach. The system employs filters made of gravel and the roots of local plants, specifically Strelitzia reginae and Cyperus alternifolius, to naturally and effectively filter wastewater without odor (Refs 2, 3, 4).
The nature-based system purifies wastewater over an area of 2,000 square meters, with a capacity equivalent to serving 900 residents. This approach offers several advantages, including reduced maintenance costs due to its simplicity, decreased energy consumption compared to traditional treatment methods, and improved water quality released back into the environment (Ref 2). Beyond its technical efficiency, the filter gardens enhance biodiversity (Ref 2) by improving the quality of water discharged into the environment and providing habitats for various species. The solution also integrates seamlessly into the landscape, showcasing vibrant flowers native to the area (Ref 1).
Additionally, the project implementers plan to construct a walking path, provide recreational equipment, and install benches to encourage residents to utilize the area as a public green space (Refs 2, 5).

The "Plan Arbre" is a tool for ecological planning and renaturation aiming to plant 308,000 trees between 2023 and 2029, sourced from the municipal nursery with seeds purchased from local suppliers (Ref 1, Ref 2). In 2023, 14,922 trees were planted, with plans to double this number in 2024 (Ref 1). The project addresses the loss of 50% of Marseille's natural spaces over the past 75 years, aiming to reverse this trend and reintroduce nature into the urban environment (Ref 2). It also tackles issues like drought and heatwaves, particularly in summer, by using trees and shrubs to cool the air, restore biodiversity, reduce air pollution, and enhance public spaces while absorbing CO2 (Ref 2).

The plan is divided into two phases. Phase I focuses on planting in Marseille's 58 parks and 273 squares and gardens, as well as around childcare centres, schools, socio-cultural centres, and sports facilities (Ref 2, Ref 3). From 2020 to 2023, various improvements were made, including playground renovations, installation of misting systems, automatic watering, and the creation of a CrossFit area (Ref 3). Phase II will involve identifying major boulevards, avenues, and streets lacking trees to enhance the urban canopy (Ref 2).
A diverse range of tree species were selected for their drought resistance, water efficiency, and ability to attract biodiversity (Ref 2, Ref 3). The project also focuses on increasing biodiversity and managing invasive species through natural methods to protect trees from pests without chemicals (Ref 3). Furthermore, the initiative includes de-impermeabilizing soils and implementing a smart irrigation system with tensiometric sensors, developed with the start-up GreenCityZen, which has saved 66% of water in two years (Ref 3). The Plan Arbre also promotes citizen participation, with 23 parks selected for community gardening projects, where ten winning associations will receive plants from the municipal nursery (Ref 1).

The city of Thessaloniki is tackling the energy crisis and climate change risks by prioritizing the installation of green roofs and green walls on school and municipal buildings as part of its resilience strategy, Thessaloniki 2030 (Ref 1, 2). One key project under this strategy has been implemented at EPAL Stavroupoli, one of the largest school complexes in the metropolitan area. The school, with a total built area of 11,918 sq.m and roof surfaces covering 6,042 sq.m, now includes a green roof covering 3,087 sq.m with 25,000 ground-cover plants, along with a vertical garden on three walls at the entrance, covering 100 sq.m and featuring 3,098 plants (ibid.).
The project is expected to yield multiple environmental benefits, such as reduced energy losses, improved thermal performance, enhanced sound insulation, better rainwater management, decreased runoff, and retention of harmful particles, all of which contribute to upgrading the area's green infrastructure (Ref 1). This initiative also strengthens the green fabric of western Thessaloniki and improves the local microclimate while addressing rainwater management issues (Ref 3, 4).

The Helmut Zilk Park, named after the late Mayor of Vienna, is located in the heart of the city, near the central train station. Surrounded by newly constructed residential and office buildings, the park serves as a vital green space, offering a variety of amenities. From playgrounds and sports fields to a community garden and cafés, it provides a space for social interaction and recreation. The park is characterized by large open meadows, which function as rainwater seepage areas, and features over 500 trees along its pathways., as well as community gardens. Flower groves enhance the park’s visual appeal while also providing habitats for local wildlife. The natural edges of the park create a diverse urban biotope that supports various plant and animal species. Grass and meadow communities have been carefully planned to enhance biodiversity and provide wet, humid habitats that help infiltrate rainwater from the surrounding paved areas. Already in its first year, the park has become home to insects, small animals, and even larger species like rabbits and snakes, contributing to its rich ecosystem.
The park was developed by the local municipality of Vienna on a site that was once part of the city's railway track system. It is the largest park the city has created in the past 40 years, designed to serve as a recreational area for both local residents and travelers using the nearby train station.
This project is part of a broader urban development initiative around the former Southern Railway station, led by Austria’s Federal Railways Company (ÖBB) and the City of Vienna. The plans included residential housing, office spaces, social infrastructure, and the creation of the Helmut Zilk Park.
Spanning approximately 70,000 square meters, the park stands as the largest public green space created in Vienna in four decades. The central area of the park features a large lawn, perfect for picnics, ball games, and recreational activities. (Ref. 1, 2, 3, 8)

North Bull Island is a national nature reserve located in Dublin Bay on the north side of Dublin. Supporting both local and migratory wildlife, the area holds several nature conservation designations. It is designated as a special amenity area for its aesthetic and recreational value and forms an integral part of the Dublin Bay Biosphere. The Island, with its 5 km beach located within the capital city and close to the city center, serves as a unique and important public amenity. (1)
The Island is estimated to attract up to 1.4 million visitors annually, including walkers, swimmers, beachgoers, birdwatchers, nature enthusiasts, kite-surfers, and various other interest groups from the local area. Additionally, it is a popular destination for schools, universities, and visitors from Ireland and abroad who come to experience accessible examples of ecological succession across nationally and internationally significant habitats, and to learn about the intricate stories that make North Bull Island Nature Reserve central to a UNESCO Biosphere Reserve and part of a global network of Biosphere Reserves. (1)
The Island and Nature Reserve are managed by the Parks, Biodiversity, and Landscape Services of Dublin City Council in collaboration with the National Parks and Wildlife Service. Dublin City Council has prepared an Action Plan for North Bull Island for 2020-2025 to implement the objectives of the North Bull Island Management Plan 2020. The North Bull Island Oversight Forum, which represents a range of stakeholders, monitors the action plan’s implementation (2). The goal is to conserve the island's environmental qualities and scientific significance while balancing its recreational and amenity value for the benefit of the local community and visitors (8).